The state of Tennessee, any department or division thereof, or any county or incorporated municipality in this state with a population of more than five hundred (500) by the last federal census, is authorized to make application for funds under the provisions of any act of congress heretofore or hereafter enacted making grants, loans or advances to the states, or any department or division thereof, or any county or municipality, for the purpose of aiding in the financing of public works. Municipalities with a population of less than five hundred (500) by the preceding federal census may make application through the appropriate agency of the county in which they are located.